Flexible circuits (e.g., “flex circuits”) may include one or more electrical components and/or electrical conductors mounted or otherwise formed on a flexible plastic substrate. In some cases, flexible printed circuits may be formed by a screen printing process. In doing so, the flexible circuit may be configured to conform to a particular shape or to flex or otherwise deform during use. In some cases, the flexible circuit may comprise a passive wiring structure that may be used to provide an electrical connection between a stationary device and a moving device. For example, a linear actuator may include a stationary component and a moving component configured to move in a linear relationship to the stationary component.
Once such linear actuator may include a voice coil actuator that may be configured for a defined motion profile. For example, the linear actuator may be configured for a short stroke (e.g., less than about 2 inches, less than about 3 inches, etc.) application, such as a closed loop servo application. Advantages to using such a linear actuator may include a compact size, such that the linear actuator may fit in a small space, very low electrical and/or mechanical time constant to improve responsiveness and/or a low moving mass that may allow for high accelerations of light payloads. Linear actuators may be used in applications requiring precise force control due to a close relationship between a linear force associated with the moving linear actuator versus the current characteristics of the device.
Some applications may be configured to control the movement of the linear actuator based on the noted relationship between current and a resulting force. In some cases, the force may be proportional to an acceleration of the moving portion of the linear actuator. In such current control applications, to other system forces such as friction, may be minimized to produce a desired accuracy. In some cases, however, a flexible circuit providing one or more electrical signals to or from the moving component may experience a torsion causing at least a portion of the flexible circuit to deform. In such cases, a portion of the deformed flexible circuit, or any other moving component, may contact a portion of the stationary component as it moves in relation to the moving component. As a result of the contact, a frictional force may be created that, in turn, may reduce the accuracy of the linear actuator. As such, a need for a flexible printed circuit capable of elimination of at least a portion of a torsional spring effect experienced in current flex circuit designs has been recognized.